Mac on Stock VGA Screen Via Backup Camera Input

I have a Honda Ridgeline with nav computer and recently I learned that with a simple homemade plugamajig, I could get video onto my nav screen. I tested my mac latop on a TV using a small video adapter and Itunes with cover flow looks just fine. You wouldn't want to surf the web this way, but you could definately use it for multimedia just fine. So I tested the thing out via my $3 homemade plugamajig and it worked right off the bat. One problem, of course...you have to be in REVERSE to see the image. Not exactly a convenient feature.

I figured out a way around this, though. By tricking the nav computer into thinking it was in reverse, you can drive all over town with the video on the screen. I did this by jacking into the rear power outlet and sending the positive current into the reverse signal wire. Doing this directly would mean that I could never see my nav system or radio controls, though, so I built a little box with a switch on it (wired in a diode to I didn't send the 12v back UP the reverse signal...not sure what that would do...turn on my reverse lights while in drive maybe?) and tada -- I can now jump back and forth (while in drive) between the nav system/radio and the video input.

While I was at it, I decided I may as well throw in a backup camera too, so I added a second switch, two video inputs and one video output. Now I can switch back and forth between the camera and the computer.

The most amazing thing is, all this worked the VERY first time I tried it. And I have no real electronic background. The only side effect is, when you're in "reverse mode", the nav computer thinks you're driving around backwards and has you all over the map. So if you need to chart a course, you're not going to want to have the screen on. It only takes about a minute for the nav computer to get back on the right track, though, so not a big deal unless you're a heavy nav computer user.

Here's the diagram of how I wired everything:

I installed the backup camera and that works fine. Kinda funny to drive around and see the cars behind you on the screen. Now all I need is a Mac Mini...the whole reason I started this project.

rear camera input?

The nav computer on my Ridgeline has an input for the backup camera video. It's not ready for an RCA connection, though. It's only a pin connection. I found info on another site that showed how to build a simple RCA plug-to-pin connection that worked perfectly.

It's pretty simple to make. You ignore pins 1, 3 & 4. Using a female RCA wire cut off at about 6" in length, attach the ground (outer) wire to pin 2 and the video (inner) wire to pin 5. Then you take a short wire and connect pin 6 to pin 7. Just a little jump from one to the other.

There's a better photo of the connector plugged in to the nav in post #23.

That'll get your video into the nav. Then you need to power the camera. This is simple to do as well, once you figure out which wire to use. I'm not having luck finding the diagram I used to identify the power wire, unfortunately. I do remember it was green. I just spliced into that wire using a plastic splicing connector and that was it. It works. When you plug in the video connector, the nav computer recognizes that a camera is connected. The green wire supplies power when the car is put into reverse and tells the computer to switch the screen to the camera signal.

You post is really interesting. I really want to do what you have done. However, I don’t really understand your diagram. Can you explain a little more about “I did this by jacking into the rear power outlet and sending the positive current into the reverse signal wire?” would you post some pictures of what you have done? Thanks!

The green wire is the reverse light signal wire. It comes from under the dash and runs to the nav computer under my seat. All that is factory installed. The purpose of the green wire is to tell the nav computer when the car is in reverse, so it will switch the screen over to the backup camera. The only way to activate the backup camera screen is to tell them nav that the reverse lights are on.

To trick the nav into thinking I'm in reverse, when I'm actually in drive or park, is to send another electrical signal into the computer. When you do this, it will switch the screen to the backup camera (or whatever video source you have plugged in) no matter what gear you're in.

I accomplish this trick by sending another electrical source into the green wire. I used the backseat power outlet (located in my center console between the front seats) as the source. I used a splicing clip to tap into the + wire at the outlet and I run that new wire into my switch box. That's the "A" wire in my diagram.

I cut the green wire near the nav computer and run then end that's attached to the computer into the switch box (wire "C"). So now I have two wires in my switch box -- the "always on" wire from my power outlet ("A"), and the nav computer green wire ("B").

"A" and "C" are attached to a switch. The switch simply controls the "A" wire's signal, on and off. The "C" wire that runs to the nav computer is attached to the other side of the switch. When switched on, the power from the "A" wire runs into the "C" wire, tricking the nav computer into thinking it's in reverse and turning the screen over to the reverse camera (or another video source you have running into there). Turn it off, and the computer thinks you're in another gear and switches the screen back to normal.

I also want it to work automatically, too, as it's intended (backup camera turning on when I go into reverse, off when I go into another gear). So I run the other half of the cut green wire into the switch box (wire "B"). This is the signal from the dash that normally tells the computer when the car is in reverse. I attached this to the "C" wire, no switch. So when the car is in reverse, the signal runs into the nav computer and functions normally. However, I added a diode between "B" and "C". A diode is controls the signal flow, one way. It lets power run from "B" into "C", but it will stop power from running from "C" back up "B" (that would be coming from "A" when switched on). I don't know what would happen if I ran power up "B" while in drive, but I didn't want my reverse lights turning on so I did this just to make sure.

So, under normal driving situations, with the switch turned off, everything works normally. I go into reverse, the signal runs down the green wire, detours into the switch box via wire "B" and flows into wire "C", and then into the nav computer. The nav screen switches over to the backup camera. While in drive, if I want to switch the screen over to the backup camera, I hit the switch and the power from the rear outlet flows into the "A" wire, into the "C" wire (getting stopped by the diode from going up the "B" wire) and then into the nav computer.

Make sense?

The other thing I did, using the same switch box, was control the video source the nav computer gets. A second switch toggles back and forth between the backup camera video and another video source that I can plug into the switch box. Whatever I want. My plan was to send a computer signal into this. You could send a DVD player, too, though that would be illegal to use while driving.